The goal is to develop a sensitive diagnostic sensor for transmissible spongiform encephalopathy (TSE) that can identify the presence of the abnormal protease-resistant, PrP(SC), conformer in biological materials before they enter the human food, blood or pharmaceutical product inventory. Unlike present commercial diagnostic assays for PrP(SC), the proposed detection system would be applicable to pre-symptomatic animals and body fluids. Furthermore, the sensor concept has inherent adaptability to be modified for any given species-originating TSE strain. For Phase I we will test the feasibility of the concept for detection of bovine spongiform encephalopathy (BSE). We are proposing a conformation-dependent assay that exploits the very nature of the TSE disease, the catalytic conversion of a largely alpha-helical protein, PrP(C), into a largely beta-sheet conformer, PrP(SC). The catalytic propagation of conformational change will be detected with a designed target peptide having a fluorescence reporter that responds to the alpha-helical to beta-sheet transition. Key to the sensor concept is that prion diseases are a process of conformational change responding to a driving force, the binding of the abnormal conformer to the normal protein and that propagation of conformational change is directly correlated with "infectivity." PROPOSED COMMERCIAL APPLICATION: Beef and beef-by-products are omnipresent in foods, drugs, vaccines, and cosmetics, and the subclinical presence of an undiagnosed epidemic of transmissible spongiform encephalopathy (TSE) could have devastating economic and human consequences. The benefits of developing a sensitive diagnostic test that can reliably identify the infectious agent in a variety of sources (including animals that are presymptomatic) before these materials enter the market for human use will be extensive.